The present invention relates to a cutting tool in general and to hedge shears in particular.
Conventional manual hedge shears, most often used for cutting shrubs and hedges, comprise two handles with blades arranged as axial extensions of the handles. These handle-and-blade combinations are pivoted together at one point, the pivot point being typically located on the blades, close to the point where the blades are attached to the handles. The blades are arranged to cross so that, when they are moved back and forth, a cutting scissor action is produced. The cutting force that can be applied to the branches to be cut with these conventional hedge shears is directly proportional to the force used for bringing the handles toward each other. This is based on a typical lever construction where the cutting force can be increased by extending the length of the handles, i.e. the operating levers; however, this is only possible to a very limited extent without the shears becoming unreasonably clumsy to use. Due to direct force transmission, manual hedge shears are relatively heavy to use, particularly on shrubs with even slightly thicker branches.
It is an object of the invention to present a cutting tool, particularly hedge shears, where an improved cutting force has been achieved without the tool becoming unreasonably clumsy or structurally complex and unreliable. This is achieved with the a cutting tool, particularly hedge shears, of the invention comprising
a first elongated handle member;
a second elongated handle member pivotally connected to the first handle member at a first pivot point;
a first blade member having a cutting edge and being pivotally connected to the first handle member at a second pivot point; and
a second blade member having a cutting edge and being pivotally connected to the second handle member at a third pivot point, the first and the second blade member being pivotally connected to each other at a fourth pivot point, the blade members being turnable relative to the fourth pivot point so that their cutting edges move in a scissor-like manner between an open and a closed position, the first, second, third and fourth pivot point forming a quadrangle in which an angle the vertex of which is formed by the first pivot point is approaching but not reaching 180xc2x0 when the blade members are approaching their closed position, whereby the work done to close the shears creates a force which tends to close the blade members and is the bigger the closer the blades are to their closed position.
The idea of the invention is to provide a pivot mechanism which allows the cutting force to be significantly increased particularly towards the end of the cutting operation, without increasing the strain experienced by the user.
Other advantages of the invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific embodiments are only given by way of illustration since, from this detailed description, various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.